package catalogue

import (
	"fmt"
	"strings"
)

// How loud a module's unhealthy condition is (novox/hq ADR 0355, extending ADR 0240).
//
// **A module may declare its unhealthy urgent.** A module whose failure costs people something they rely on
// (mail refused or stuck for everyone with a mailbox) says so with `unhealthy`, and its condition
// `module.<module>.<machine>.unhealthy` is raised urgent instead of a warning. **Urgent needs a why**, as an
// `upgrade` policy other than roll does: a person reading the catalogue sees what is lost while it is broken.

// The severities a module may declare for its unhealthy condition.
const (
	// UnhealthyUrgent raises the module's unhealthy condition urgent, on every machine it runs on.
	UnhealthyUrgent = "urgent"
	// UnhealthyWarning is what a module's unhealthy condition is without the field, said out loud.
	UnhealthyWarning = "warning"
)

// UnhealthyPolicy is what a module says about how loud its unhealthy condition is: `unhealthy` in its manifest
// (novox/hq ADR 0355).
type UnhealthyPolicy struct {
	Severity string `json:"severity"`
	// Why names what people lose while the module is broken. It is required: a module that says nothing of
	// why it is loud is refused.
	Why string `json:"why,omitempty"`
}

// unhealthyProblems refuses an `unhealthy` without a why, and any severity but urgent or warning (novox/hq ADR
// 0355 §2).
func (m Manifest) unhealthyProblems() []string {
	if m.Unhealthy == nil {
		return nil
	}
	var problems []string
	switch m.Unhealthy.Severity {
	case UnhealthyUrgent, UnhealthyWarning:
	default:
		problems = append(problems, fmt.Sprintf("unhealthy is %q or %q, not %q", UnhealthyUrgent, UnhealthyWarning,
			m.Unhealthy.Severity))
	}
	if strings.TrimSpace(m.Unhealthy.Why) == "" {
		problems = append(problems, "unhealthy says why: a module that declares how loud its failure is names "+
			"what people lose while it is broken")
	}
	return problems
}

// UnhealthyIsUrgent is whether the module declares its unhealthy condition urgent (novox/hq ADR 0355 §1).
func (m Manifest) UnhealthyIsUrgent() bool {
	return m.Unhealthy != nil && m.Unhealthy.Severity == UnhealthyUrgent
}